Y Combinator, the legendary startup accelerator behind Stripe, Airbnb, and Reddit, just wrapped up its Winter 2025 Demo Day. This batch featured 160 promising startups, many of which are laser-focused on AI—though not in the way you might expect.
Rather than building yet another AI model, a surprising number of these startups are focused on enhancing AI agents, creating the infrastructure and tools that help AI work better. With so many AI-related startups out there, these stood out from the crowd.
While there were some other interesting companies—like Optifye, which is making factory worker management software (and was recently in a social media controversy), and Artificial Societies, which simulates LinkedIn engagement—here are the startups that truly caught our attention at YC W25.
The Standout Startups of YC W25
Abundant – The Human Safety Net for AI Agents
What it does: API for agent teleoperation
Why it’s a game-changer: One of the key reasons autonomous vehicles like Waymo’s robotaxis have succeeded is that they allow human intervention when the AI gets stuck. Abundant applies that same concept to all AI agents. Its API detects when an AI agent fails and seamlessly lets a human operator take control. That means fewer AI blunders and a much smoother user experience.
Browser Use – AI Agents That Can Navigate the Web
What it does: Enables AI to interact with browsers
Why it’s making waves: This startup went viral recently when a Chinese AI agent, Manus, used its open-source tool to navigate websites, click through menus, and fill out forms—causing daily downloads to skyrocket to 28,000. As AI-powered web browsing tools like OpenAI’s Operator gain traction, Browser Use is positioning itself as the must-have tool in the space.
GradeWiz – No More Tedious Grading for TAs
What it does: Automates grading for teaching assistants
Why educators will love it: Teaching assistants are essential to universities, but grading endless papers isn’t the best use of their skills. Created by Cornell TAs who openly admit they “hate grading,” GradeWiz uses AI to handle the grunt work—freeing up TAs to focus on actually teaching.
Misprint – The Robinhood of Pokémon Cards
What it does: A stock market-style marketplace for collectibles
Why it’s a winner: Co-founder Eva Herget quit her job at Goldman Sachs to sell Pokémon cards full-time, making $40,000 a month. Now, she’s turning that expertise into Misprint, a platform where users can buy and sell Pokémon cards like stocks, using a bid/ask system. With a $3.5 billion secondhand market for Pokémon cards, this startup is playing a serious game.
Nextbyte – Finding the Best ‘Vibe Coders’
What it does: AI-powered hiring tool for AI-assisted coding
Why it’s relevant: AI-assisted coding isn’t just a shortcut—it’s a skill. With a quarter of YC startups now using AI-generated codebases, companies need developers who know how to leverage AI effectively. Nextbyte uses AI to assess a coder’s ability to work with AI tools, ensuring companies hire the best ‘vibe coders’ out there.
Pickle – Your AI Clone for Zoom Calls
What it does: Creates a real-time AI clone for video meetings
Why it’s a lifesaver: Ever jumped on a Zoom call with messy hair and pajama pants? Pickle lets you create a polished AI clone of yourself that lip-syncs to your voice in real-time—so you can look professional without actually being camera-ready. With over 1,500 paying users already, this one is making remote work even more convenient.
Rebolt – AI-Powered Restaurant Management
What it does: Automates restaurant inventory and supplier management
Why it’s valuable: Restaurant management is chaotic—often relying on Google Sheets and endless phone calls. Rebolt uses AI agents to streamline inventory and supplier coordination. It’s already in talks with the parent company of Burger King, signaling big potential.
Red Barn Robotics – A Roomba for Weeds
What it does: AI-powered weeding robot for farms
Why it’s essential: Weeds are a farmer’s nightmare, requiring massive amounts of labor to remove. Red Barn Robotics, founded by a former Apple hardware lead, built an autonomous weeding robot called “The Field Hand,” which it claims is 15x faster than humans at a quarter of the cost. With $5 million in preorders, farmers seem to agree.
Retrofit – AI-Powered Vintage Shopping
What it does: Curates vintage fashion with AI
Why fashionistas will love it: Shopping for vintage clothing online can be overwhelming. Retrofit uses AI to analyze thousands of listings and curate selections based on trends and quality—making thrifting easier than ever.
Splash Inc – The Future of Autonomous Naval Patrols
What it does: Builds AI-powered patrol boats
Why it’s exciting: The defense industry is going all-in on autonomy, and Splash Inc is riding the wave. Their autonomous patrol boats are designed to monitor sea borders and have already autonomously traveled 200 miles in the San Francisco Bay Area with an impressive 800-mile range. With growing interest in AI-powered defense, Splash Inc could be set for smooth sailing.
Final Thoughts
YC Demo Day never fails to introduce the world to game-changing startups, and this batch is no different. Whether it’s AI-powered grading, restaurant automation, or Pokémon card trading platforms, these companies are pushing the boundaries of what AI can do.
One thing is clear: The future of AI isn’t just about building better AI agents—it’s about building the tools that make AI smarter, faster, and more reliable. And these YC W25 startups are leading the charge.
